It will explode as a type Ia supernova.

White dwarfs with masses greater than the Chandrasekhar limit, the upper limit upon which white dwarfs can resist their own gravity due to the Pauli Exclusion principle.

The currently accepted value of the Chandrasekhar limit is 1.44 solar masses.

Subrahmanyan Chandrasekhar calculated the famous "Chandrasekhar Limit" and did a lot of other seminal work in astrophysics. The Chandra X-ray space observatory was named in his honor.

When the mass exceeds the Chandrasekhar limit.

The Oppenheimer Limit is actually known as the Tolman-Oppenheimer-Volkoff Limit and is related to astrophysics. The limit is similar to the Chandrasekhar limit in the sense of limits. The Chandrasekhar is the accurate limit in which electron degeneracy can no longer resist gravity of massive stars of 1.44 stellar masses or more and force the electrons into the protons to become neutrons. The Oppenheimer Limit basically states within a certain mass(Currently unknown exactly!), the neutron will break down into quarks or other subatomic particles, or collapse into a black hole.